We are attempting to isolate the specific, hormone-regulatable phosphatase which converts liver glycogen synthetase from the b to the a form. We are also investigating the basis of the increase in total synthetase activity which is obtained on incubation of the enzyme with certain tissue fractions. We are also studying the chemistry of the phosphofructokinase protective factor which we have isolated from liver and the relationship, if any, between its effect and the reported interconversion of phosphofructokinase between active and inactive forms. BIBLIOGRAPHIC REFERENCES: H.L. Segal, "Enzymes of Glycogen Metabolism and Their Control", in "Physiological Effects of Food Carbohydrates", A. Jeanes and J. Hodge, eds., ACS Symposium Series 15, American Chemical Society, washington, 1975, p. 235. L. Sankaran, R.T. Proffitt, B.M. Pogell, G.A. Dunaway, Jr., and H.L. Segal, "Liver Peptide Stabilizing Factor Protects Phosphofructokinase against Inactivation by Fructose-1,6-Biphosphatase", Biochem. Biophys. Res. Commun. 67, 220 (1975).